DNase Activity

Many Colicins exhibit enzymatic DNase activity as their cytotoxic activity to kill the targeted E. coli cell. The structure shows the DNase domain of Colicin E9 bound to its Colicin Immunity Protein, Im9. These kill the cell by selectively cleaving the DNA throughout the genome, which ultimately leads to cell death as the damage is too great for the cell to repair itself. Rather than continue to live with a faulty genome, the cell kills itself.

This shows just the Colicin E9 DNase domain, as bound to Im9. Here instead shows just the Im9 immunity protein.

Colicins with DNase activity
Colicin E2 Colicin E7 Colicin E8 Colicin E9